To test tire tread depth, there are several simple and effective methods you can use:
- The Coin Test (Penny or 20p Coin Test) :
- Take a penny (in the U.S.) and insert it into the tread groove with Lincoln's head upside down and facing you.
- If you can see the top of Lincoln's head, the tread is less than 2/32 of an inch and the tire should be replaced.
- In the UK, use a 20p coin: insert it into the tread grooves, and if you can see the outer band of the coin, your tire tread may be below the legal limit and unsafe.
- The quarter test is another option: if the tread touches Washington's head on the quarter, you have at least 4/32 inch of tread left.
- Tread Wear Indicator Bars :
- Most tires have tread wear indicators molded into the tire grooves, visible as small bars.
- If the tread is worn down to these bars, which usually indicate 2/32 of an inch depth, it's time to replace the tire.
- Tread Depth Gauge :
- A specialized tool called a tire tread depth gauge can measure tread depth precisely.
- Insert the gauge into the tire groove and read the measurement, usually in millimeters or 32nds of an inch.
- Check multiple locations around the tire and use the smallest reading for the most accurate assessment.
For safety, tires are generally considered legally worn out when tread reaches 2/32 of an inch (about 1.6 mm). However, many experts recommend considering replacement once tread depth falls to about 4/32 inch, especially in wet or snowy conditions to maintain proper traction. Regularly test tires, especially before long trips or every couple of weeks, to ensure safe driving conditions. These simple methods help you know when to replace your tires for safety and legal compliance.
